The present invention relates to packaged integrated circuits, and more particularly, to bonding pads of integrated circuits that are packaged and have wire bonds.
Integrated circuits are continuing to become smaller and more complex. As circuit complexity has increased, so has the need for more input and output signals. Ball grid array (BGA) is an important package type for integrated circuits that typically uses wire bonds in making electrical connection between the integrated circuit and one part of the BGA package. BGA packages generally have an integrated circuit mounted on a top side of a package substrate and an array of solder balls on a bottom side of the package substrate. Then, bonding pads on the integrated circuit are connected to wire bond fingers on the package substrate with wires. The wire bond fingers typically are connected to traces, which in turn are connected to via capture pads to vias and finally to the solder balls on the bottom side of the package substrate.
Wirebonding machines use pattern recognition software to locate the wires on the bonding pads. However, as the number of I/O signals has increased, there are more bonding pads and therefore more wires, yet the size and pitch of the bonding pads has decreased. Thus, it can be difficult to reliably connect the wires to the bonding pads. Common problems are wires shorting with other wires and wires not staying attached or making good electrical contact with a bonding pad.
BGA packages are particularly beneficial for high performance integrated circuits in which low cost is significant. This applies to many integrated circuits such as microcomputers and static random access memories (SRAMs).